Wilhelm kael jose



W. K. J. RUDOLPH.

MULTIPLE CONTACT MICROPHUNE. APPLICATION FILEDv FEB. 24. 1915. RENEwEDD'c.2.191.

T Patented Sept. 9, 1919.

l l 5y 3 yf I p y JE .mwa y 1 vvmirino sTATEs PATENT orsi-cn.

f KWILHLM KARL JOSEF RUDOLPH, 0F KIEL, GERMANY, ASSIGNOR '1'0 THE FIRMSIGNAL GESELLSCHAFT M. B. H., OF KIEL, GERMANY.

MULTIPLE-CONTACT MICOPONE.

` Specification of Letters Patent.

Patented sepas, 191e.

-Application filed February 24, 1916, Serial No. 80,190; RenewedDecember '2, 1918. Serial No. 265,051.

To all whom t may concern:

Be it known that I, WILHELM KARL J oser RUDOLPH, a subject of the GermanEmperor,

and residing at Kiel, county of Schleswig- I-Iolstein, State of Prussia,Germany, have invented certain new and useful Improvements inMultiple-Contact Microphones, of which the following is a specification.

The invention relates to multiple-contact microphones of the typewherein the prejudicial effect of polar forces acting upon the granularfilling, and the agglomeration of the carbon grains resulting from saideffect shall be avoided b the carbon room being subdivided in a purality of compartments or cells by means of an intermedlate piece ofmore or less elastic material.

Arrangements of this kind are knownin many forms, but, thearrangementshitherto used leave much to be desired with regard to the safet ofeffectiveness and to the damping of t e microphone.

According to the invention, the desired object is obtained free fromobjections by using for the subdivision of the carbon room anintermediate piece of velour cloth (velvet or plush) the hairs of whichmay as far as possible lie in the same direction and are,

' without exception, inclined to the plane of the ground cloth or of theelectrodes.V In order to avoid fringing the cloth during the shaping ofthe same, and to prevent carefull the jutting out of coarse threads, theclot piece may previously be gummed on to a thin lining consisting of ahomogeneous material 'for example of paper or the like, which a fer theshaping isterminated serves for fixing the intermediate of theelectrodes. V

In this manner, with a nearly" complete yutilization of the spaceavailable 4between the electrodes, a very elastic subdivision of thefilling room is obtained, which not only continually loosens'thegranular filling on the cessation of the jerks but also allows themicrophone damping to be reduced at will. Thatis to say, one can varythe damping continuously, by changing the distance be tween theelectrodes, without at the same time finding it necessary to change thelength ofthe little hairs which are all in-' clinedin the same way tothe electrode.

When the distance between the electrodes s` made less, the hairs as awhole, uniformly piece on to one assume a greater inclination to theplane of said electrodes, and vice versa.

According to the invention, a particular advantageous operation isfurther obtained with microphones having a filling of granules ofdifferent sizes and weights b the feature that the hairs of the clothwhich is used for the subdivision of the carbon room,

that manner there is obtained a continued remarkable sensitiveness ofthe microphone to sounds of different frequencies which-thus may berenderedas, truev to nature as possible. Withlthe same thickness ofgrains the difference in weight may be obtained, for

example, by using metal grains or hollow balls or generally grains ofdifferent specific weight which are coated with carbon or anothermaterial of suitable conductivity. Or-

dinarily it may be suiicient to employ carbon grains of varying sizes.

In the accompanying drawings, an em bodiment of the invention isrepresented by wayof an example. lFigure 1 is a plan view of a gridshaped intermediate plece illustrating the prlnciple of the invention;Fig. 2 shows a central sectional elevation of lmicrophone electrodesprovided `with said intermediate piece; Flg. 3 represents a cen-- tra]sectional elevation ofa microphone constructed according to theinvention, the carbon room being subdivided into a plurality ofcompartments filled with grains of different sizes.

In the drawings a designates a id shapled intermediate piece formed ofve our clot l gummed on to the rear side-of the round cloth before thepiece is shaped. Wlth the aid of the said lining b the piece a isgulnmed onto the electrode c of the microphone. The hairs It of theintermediate piece are inclined -in the same direction to the plane ofthe ground cloth so as to project obliquely upward orf downward and toVtouch the second electrode d of the microphone. The hairs Ithold inelastic susand provided with a lining b of paperV pension the granularfilling e contained the ycells which `are formed by the grld shapedpiece a. Careful attention is to be paid to having as much as possibleall of the hairs inclined in the same direction, in order to avoiddisturbing their uniformity when regulating the damping of themicrophone. 'A

It will be observed that when the hairs are inclined to the faces of theelectrodes.

Corresponding to Fig. 3, the cells which are formed between theelectrodes 0 and d by the intermediate piece a are filled with carbongranules e of different thickness and weight, increasing by compartmentsfrom the top to the bottom. In this way sounds of dierent eharacter'maybe recelved and rendered as true to nature as possible by la suitablediaphragm g coupled with the electrode d.

What I claim is:

1. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth, said cloth havingits bottom ortion fixed/to one of the electrodes and t e vfine hair ortog portion touching the other electrode of sai microphone.

2. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth, said cloth havingits bottom ortion fixed to one of the electrodes and t e fine hair ortop portion touching the other electrode of said microphone, the oundwarp of said cloth being fixed to a llning of homogeneous material suchas paper, so as to prevent fringing,

3. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth,

said cloth having its bottom portion fixed to one of the electrodes andthe fine hair or top portion touching the other electrode of saidmicrophone, the ground warp of said cloth-being fixed to a lining ofhomogeneous material such as paper, before shaping the cloth, so as toprevent fringing.

4. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth the hairs of whichare inclined in the same direction` to the plane of the ground warp andof the electrodes.

5.l 'A granular microphone having its fills heimat? 'ing room subdividedinto a plurality of coiiipartments -by means of velour cloth the groundwarp of which is fixed to a lining of homogeneous material such as paperand the hairs of which are inclined in the same direction to the planeof the ground warp and of the electrodes.

6. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth the ground warp ofwhich is fixed to a lining of homogeneous material such as paper be;

fore shaping said cloth the hairs ofwhich are inclined in the samedirection to the plane of the ground warp and of the electrodes.

7. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth said strips subdividing the fillingroom of the microphone into a plurality of compartments.

' 8. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth the hairs of which are inclined in thesame direction to the plane of the ground Warp and of the electrodes,said strips subdividlng the filling rooln of the microphone into aplurality of compartments.

9. A granular microphone having between the electrodes, intermediatestrips consisting of velour cloth, said cloth having its bottoni portionfixed to one of the electrodes and the fine hair or top portion touchingthe other electrode, the ground Warp of said cloth being fixed to alining of homogeneous material so as to prevent fringin ,said stripssubdividing the llin room o the microphone into a plurality ofcompartments.

10. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth, said cloth having its bottom `portionfixed to one of the electrodes and the fine hair or top portion touchingthe other electrode, the round Warp of said cloth being fixed to alining of homogeneous material before shaping the strips, so as toprevent fringing, said strips subdividing the filling room of themicrophone into a plurality of compartments.

1l. A granular microphone having bctween the electrodes intermediatestrips consisting of velour cloth, the ground warp of which is fixed toa lining of homogeneous material, and the hairs of which are inclined inthe same direction to the plane of the ground warp,- said stripssubdividing the filling room of the microphone into a plurality ofcompartments.

12. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth the ground warp of hairs of which areinclined in the same direunion to the plane of the ground warp, saidstrips subdividing the lling room 4of the microphone into. a pluralityof compartments.

`13. A granular microphone having its filling room subdivided into aplurality Ofcompartments by means of a gridfshaped intermediate piececonsisting lour cloth, said cloth' having its bottom portion fixed toone of the electrodes and its t line hair or top portion touching theother electrode of said microphone.`

145. A granular microphone having its filling room subdivided into aplurality of compartments by means of a grid-shaped intermediate piececonsisting of one piece of velour cloth, said cloth having its bottomportion fixed to one of the electrodes and its fine hair or topportiontouchin the other electrode of said microphone, tie ground warpof said cloth being fixed to a lining of homogeneous material suchaspaper, so as to prevent fringing.

15.` A granular microphone having its filling room subdivided into aplurality of compartments by -means of a grid-shaped intermediate piececonsisting of one piece of velour cloth, said clothy having its bottomportion fixed to one of the electrodes and its line hair or top portiontouching the lother electrode of said microphone, the ground warp ofsaid clothbeing fixed to a lining of homoof one piece of vegeneousmaterial such as paper, before` shaping the intermediate vent frlnging.Y

l1,6. A granular microphone having its lling room subdivided into aplurality of compartments by means o f a grid shaped intermediate piececonsisting of one piece of velour cloth' the hairs of which are inpiece,so as to'preclined in the same direction to the plane of the ground Warpand of the electrodes.

17. A granular microphone having its filling room subdivided into aplurality of compartments by means of a grid shapedV intermediate piececonsisting of one piece of velour qloth having its ground Warp gummed:on to a lining of homogeneous material and its hairs inclined in thesa'me direction to the and of the electrodes.

18. A' granular microphone having its filling room subdivided intoaeplurality 4of compartments by means of a grid shaped plane of theground Warp intermediate piece consisting of one pieceA of velour clothf'having its ground warp gummed on to a lining of vhomogeneous materialbefore shaping the intermediate piece the hairs of which are inclined inthe same direction to the plane of the ground warp and of theelectrodes.

19. A granular microphone having its filling room subdivided into aplurality of compartrnents by means of a grid-shaped intermediate piececonsisting of one piece of vesaid intermediate partments lour cloth,said cloth having its bottom por# tion fixed to one of the electrodesand the fine hair or top portion touching the other electrode of saidmicrophone, the edge strip of said intermediate piece surrounding thefilling rooma 20.' A granular microphone having its vfilling roomsubdivided into a plurality of com# by means of a grid-shaped inten,

mediate piece consisting of one piece of velour cloth,v said clothhaving its bottom portion fixed to one of the electrodes and its finehair or top portion touching the other electrode of said microphone, ofsaid cloth being fixed to geneous material so the edge strip of a liningof homoas to prevent fringing, said intermediate piece surrounding thefilling room.'

21. A granular microphone having its filling room subdivided into aplurality of compartments by means `of a grid-shaped intermediate piececonsisting of one piece of velour cloth,` said cloth having its bottomportion fixed to one of the electrodes, and its 'ne hair or top portiontouching the other electrode of said microphone, the ground Warp of saidcloth being fixed :to a lining of homogeneous material before shapingthe intermediate piece, so as to prevent fringing, the edge strip ofsaid intermediate piece surrounding the filling room.

22. A granular microphone having its filling room subdivided into aplurality of compartments by means of a grid shaped intermediate piececonsisting of one piece of velour cloth the hairs of which are inclinedin the sameV direction to, the plane of the ground warp and of theelectrodes, the edge strip of said intermediate piece ,surroundingthefilling room.

23.. A granular microphone having its lilling room subdivided into' aplurality of compartments by means of a grid shaped intcrmediate piececonsisting of one piece of velour cloth having its ground Warp gummed onto a lining of homogeneous ma-4 terial and its `hairs inclined in thesame dii of velour cloth having its ground Warp gummed on to a lining ofhomogeneous material before shaping the intermediate piece the hairs ofwhich are inclined in the same direction t0 the plane of the ground warpand of the electrodes, the edge strip of piece surrounding the fillingroom.

25. A granular microphone having its filling room` subdivided unto aI[plurality of compartments by means of velour cloth,

the ground Warp compartments by means of velour cloth,

said cloth having its bottom portion fixed to one of the electrodes andits fine hair or top portion touching the other electrode of saidmicrophone, the ground warp of said cloth being Xed to a lining ofhomogeneous material so as to prevent fringing,

the different compartments being filled with grains of different volumeand of different weight.

27. A granular microphone having its filling room subdivided into aplurality of compartments by means of -velour cloth, said cloth havingits bottom portion fixed to one of the electrodes and its fine hair ortop portion touching the other electrode 0f said microphone, the groundwarp of said cloth being fixed to a lining of homogeneous materialbefore shaping the cloth, so as to prevent'fringing, the dierentcompartments being filled with grains of different volume and ofdifferent weight.

`28. A- granular microphone having its filling .room subdivided into aplurality of compartments by means of velour cloth the hairsy of whichare inclined in the same direction to the plane of theground warp and ofthe electrodes, the said compartments being filled with grains ofdifferent volume and of different weight.

29. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth the ground warp ofwhich is fixed to a lining of homogeneous material and the hairs ofwhich are inclined in the same direction to the plane of the ground warpand of the electrodes, the said compartments being filled with grains ofdifferent volume and of different weight.

30. A granular microphone having its filling room subdivided into aplurality of compartments by means of velour cloth the ground warp ofwhich isfixed to a lining of homogeneous material before shaping thecloth the hairs of which are inclined in the same direction to the planeof the ground warp and of the electrodes, the said compartments beingfilled with grains of different volume and of different weight.

31. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth, said cloth having its bottom portionfixed to one yof the electrodes and its fine hair or top portiontouching the other electrode, said strips subdividing-the filling ro,o1nof the microphone into a plu# mass# rality of compartments, thedifferent cornI part-ments being filled with grains of different volumeand of different weight.

32. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth, said cloth having its bottom portionfixed to one of the electrodes and its fine hair or top portion touching the other electrode, the ground warp of said cloth being fixed to alining of homogeneous material so as to prevent fringing, saidstripsubdividing the filling room` of the microphone into a plurality ofcompartments, the different compartments being filled with grains ofdifferent volume and of different weight.

33. A granular microphone having between the electrodesintermediatestrips consisting of velour cloth, said cloth having its bottom portionfixed to one of the electrodes and its fine hair or top portion touchingthe other electrode, the ground warp of said cloth being fixed to alining of homogeroom of the microphone into a plurality of compartments,and-the different compartments being filled with grains of differentvolume and of different weight.

35. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth the ground warp of which is gummed onto a lining of homogeneous material, and the hairs of which are inclinedin the same direction to the plane of the groundwarp and of theelectrodes, said strips subdividing the fllin room of the microphoneinto a plurality o compartments, and the said compartments being filledwith grains of different volume and of different weight.

36. A granular microphone having between the electrodes intermediatestrips consisting of velour cloth the ground warp of which is gummed onto a lining of homogeneous material before shaping the strips the hairsof which are inclined .in the same direction to the plane of the groundwarp and of the electrodes, said strips subdividing the filling room ofthe microphone into a plurality of compartments, and the saidcompartments being filled with grains of different volume and ofdifferent weight.

37. A granular microphone having its filling room subdivided into aplurality of 130 compartments by means ofa grid-sha ed in.-

termediate piece consisting of one piece of velour cloth, said clothhaving its bottom lportion fixedV to one of the electrodes and its finehair or top portion touching the other electrode of said microphone, therdifferent compartments being filled with grains of- 39. A granularmicrophone having its filling room subdivided into a pluralit ofcompartments by means of a grid-shape intermediate piece consisting ofone plece of velour cloth, said cloth having its bottom l portion fixedto one of the electrodes and its fine hair or top portion touching theother electrode of said `A microphone, the ground warp of said clothbeing xed to a lining of homogeneous material before shaping theintermediate piece, so as to prevent fringing, the differentcompartments bein filled with grains of dilierent volume an of differentvveight.

40. A granular microphone having its filling room subdivided into aplurality of compartments by means of a grid shaped intermediate pieceyconsisting of one piece of velour cloth the hairs of which are inclinedin the same direction to the plane of the ground Warp and of theelectrodes, and the said compartments being filled With grains ofdifferent volume and-of different weight. i

41. A granular microphone having its filling room subdivided into aplurality of compartments by meansi of a grid shaped intermediate piececonsisting of one piece of velour cloth havingV its ground warp gummedonl to a lining of homogeneous material and its hairs inclined in the"same direction to the plane ofthe ground warp and of the electrodes,'thesaid compartments being filled with grains of different volume and ofdifferent Weight.

42. A granular microphone having its filling room subdivided into aplurality oi.' compartments by means of a grid shaped intermediate piececonsisting of one piece of velour cloth having its ground Warp gummed onto a lining of homogeneous material before shaping theintermediate-piece lthe hairs, of which are inclined in the samedirection to the plane of the ground warp and of the electrodes, thesaid com artments being filled with grains of di erent volume and ofdifferent Weight.

43. A granular microphone having its lilling room subdivided into aplurality of compartments by means of a grid-shaped intermediatepiececonsisting of one piece of velour cloth, said cloth having itsbottom portion fixed to one of the electrodes and its fine hair or toportion touching the other electrode of sald microphone, the edge stripof said intermediate piece surrounding the filling room, and thedifferent compartments being filled with grains of different volume andof diii'erent weight.

44. A granular microphone havingpits fill- `ing room subdivided into aplurality of compartments 'by means of a grid-shaped intery medlatepiece consisting of one piece of velour cloth, said cloth having itsbottom portion fixed to one of the electrodes and its fine hair .or topportion touchingV the other electrode of said microphone, the groundWarp of said cloth being `ixed to a lining of homogeneous material so asto prevent fringing, the edge strip of said inter- `mediate piecesurrounding the fillingroom,

andthe 'different compartments being filled With drains of differentvolume and of different Weight.` i

45. A granular microphone having its filling room subdivided into aplurality of compartments by means t of a grid-shaped intermediate piececonsisting of `one piece of velour cloth, said cloth having its bottomportion fixed to one of the electrodes `and its tine hair or top portiontouching the other electrode of said microphone, the ground warp of saidcloth being fixed to a lining of homogeneous material before shaping theintermediate piece, so .as to prevent fringing, the edge strip of saidintermediate piece surrounding the filling y room and the differentcompartments being filled with `grains of different volume and l ofdiferent Weight.`

46. A granular microphone having its filling room subdivided into aplurality of compartments by means of a grid shaped intermediate piececonsisting of one piece of -velour cloth the hairs of which are inclinedin the same direction to the plane of the ground warp and of theelectrodes, theedge strlp of said intermediate piece surround- Y ing thefilling room, and the said compartments being filled with grains ofdifferent volumel and of different Weight.

47. A granular microphone having its filling room subdivided into aplurality Ofcompartments by means of a grid shaped `intermediate piececonsisting ofone piece of velour cloth the ground warp ofwhich is gummedon to -alining of homogeneous material so as to prevent fringing and thehairs of` which are mclined in the same direction 'to the plane of theground Warp and of the electrodes, the edge strip of said intermediatepiece surrounding the illing room, and the said compartments beingfilled with grains of diiferent Volume and of different Weight.

48. A granular microphone having its filling room subdivided into aplurality of compartments by means of a grid shaped intermediate piececonsisting of one piece of velour cloth the ground warp of which isgummed on to a lining of homogeneous material before shaping theintermediate piece so as to prevent fringing the hairs of which areinclined in the same direction to the plane of the ground Warp and ofthe electrodes, the edge strip of said intermediate piece surroundingthe lilling room and the said compartments being filled with grains ofdifferent Volume and of diferent Weight. In testimony whereof I affix mysignature in presence of two Witnesses.

WILHELM KARL JOSEF RUDOLPH. Witnesses:

HERMANN SCHT'I, HEINRICH ScHNING.

